The objective of this proposal is to examine outcomes of a treatment intervention designed to increase functional use of complex (multi-clausal) sentences in school-age students with primary language impairments that impact literacy and academic achievement. The treatment protocol includes: (1) three types of complex sentences (adverbial, relative, object complement), (2) encounters with complex sentences in real texts and across all modalities (speaking, listening, reading, writing), and (3) activities that engage metalinguistic understanding of complex sentences. Specific objectives are to (1) document treatment effect in terms of size and scope in decontextualized as well as naturalistic language contexts, (2) document the effect of treatment intensity (dosage), (3) explore effects of sentence complexity subtype on treatment outcomes, and (4) explore relationships between treatment outcomes and participant variables (pre-treatment knowledge of complex sentences, verbal working memory, and non-verbal cognition). DESIGN: This early clinical efficacy study will utilize two designs. Ten participants per year over three years will complete the treatment, randomly assigned to one of two dosage levels. As each participant finishes, efficacy and effect size will be measured using a multiple-baseline single-subject design. Once all 30 participants have completed the treatment, effect size and the impact of dosage (treatment intensity) will be evaluated using a pretest-posttest group design, and correlations between participant characteristics and individual patterns of performance will be carefully described and analyzed. PARTICIPANTS: This study targets school-age students with a Speech-Language Impairment and/or a Specific Learning Disability between the ages of 10 and 14 who are receiving services from a Speech- Language Pathologist (SLP) for one or more higher-level language behaviors. It is expected that participants will demonstrate higher levels of fluency with complex sentences compared with pretreatment baseline levels and that treatment effects will be reflected in several modalities and in naturalistic language contexts. PUBLIC HEALTH RELEVANCE: Students with language impairments and learning disabilities account for more than 60% of all students served under IDEA Part B in schools. Reduced levels of comprehension and production of complex sentences is well documented in the population of older children and adolescents with primary language impairment, as is the impact of oral language deficits on later literacy outcomes. This investigation of treatment for specific higher-level language skills in older school-age students addresses a scarcity of controlled research in this area.